A conduit is usually employed for connection of a small motor, for example, a motor employable for a machine tool. More specifically, each opening for connection with a conduit is provided on each side of a motor frame, along the shaft thereof, and one of the two openings which is more convenient from the practical view-point, is actually employed for connection of a cable by means of a conduit, and the other of the two openings is closed by a blanking cover or a rubber plug.
However, it is not easy to hermetically seal the unemployed opening with a blanking cover or a rubber plug. Therefore, there is a drawback wherein foreign materials, for example oil or the like, enter into a terminal box.